Heat exchangers find a variety of uses in engine systems. For example, recent efforts to enhance fuel economy and/or reduce emissions use heat exchangers to cool exhaust gas in exhaust gas recirculation systems. Currently, exhaust gas recirculation (EGR) heat exchangers or coolers are constricted in either shell-tube or bar-plate form. Typically, the shell-tube type of construction provides less heat transfer in a given volume than does the bar-plate. However, bar-plate fabrication can be expensive. Thus, a need exists for heat exchangers that can provide heat transfer equivalent to, or better than, the bar-plate, while reducing the associated fabrication expense. Methods, devices and/or systems capable of reducing construction costs and/or facilitating and/or enhancing transfer of heat energy are described below.